Manga Publisher is an unknown author who works under Aki. He appears in the first chapter where his manga is rejected by Aki. And he appears in episode 21 where, both Aki and him meet at a Cafe to discuss his manga. Unlike in the book, Aki helps him improve his manga instead of rejecting it.

Dolphin's Parents are the mother and father to Dolphin. They first appear in Chapter 190 of the manga and Episode 13 of the Flash Series. they appear nearby an island when Shin Keroro notices them. They are later seen watching Shin and Dolphin say there goodbyes.

Tamama's Friends were Tamama's previous Kindergarten Friends. They first appear in Chapter 183 and Episode 12 of the Flash Series. They appear briefly in a flashback when Tamama is reminded as to why he hated pick up during kindergarten, due to the fact that no one would come to pick him up. The red tadpole has a heart symbol much like Sumomo.